Eastern Mallard Status and Issues
(mallard bag limit reduction from 4 to 2 beginning 2019/2020 season framework)
The Atlantic Flyway Council and U.S. Fish & Wildlife Service are poised to reduce the mallard bag limit in the Atlantic Flyway from 4 to 2 birds per day starting with the 2019–2020 hunting. Mallards are managed as three distinct population units including Western (California, Oregon and Washington), Mid-continent (prairie pothole region, parklands and boreal forest) and Eastern (northeast states and eastern Canada). Bag limits and season lengths for the Atlantic Flyway are primarily influenced by the population status of eastern mallards through an adaptive harvest management (AHM) framework. Band recovery information suggests that most mallards harvested from North Carolina to eastern Canada are produced within the region. In recent years, the breeding population of mallards in eastern Canada has been stable but declining in the northeastern states especially New York and Pennsylvania. The decline is significant enough to cause the current AHM model to predict restrictive seasons in the Atlantic Flyway.
Based on historical records, mallards in northeastern North America were common migrants but rarely bred there. Depletion of wild stocks due to market gunning and later the outlawing of live decoys resulted in the wholesale release of captive mallards. Thus, the release of captive reared birds was likely more responsible for mallards appearing in the northeast than eastward expansion from the core range in the Prairie Pothole Region. In fact, recent genetic studies suggest eastern mallards are more closely related to Old World mallards than their prairie brethren. Manmade modifications to the landscape allowed mallards to nest in areas previously unexploited by the species and populations of mallards in the northeast grew significantly over time as they pioneered new habitat.
Duck harvest management in the Atlantic Flyway was historically based on the status of prairie ducks and later mallards via adaptive harvest management (AHM). Drastic population declines due to drought on the prairies during the 1980s, resulting restrictive seasons (3 birds/day and 30-day seasons) and band recovery data suggesting few prairie ducks are harvested in the Atlantic Flyway served as an impetus for data collection and investigating AHM for eastern mallards. Following a decade of data collection through the Atlantic Flyway Breeding Waterfowl Survey, the Eastern Survey Area Breeding Waterfowl Survey (Canada) and intensified preseason banding, an AHM model for eastern mallards was established in 2000 and has informed harvest management in the Atlantic Flyway to present.
The eastern mallard breeding population reached a peak of 1.1 million in 2004 but has significantly declined since and last year’s estimate was approximately 650,000. While the population in eastern Canada has largely been stable, it has been declining in the northeast U.S., especially in New York and Pennsylvania. The decline since 2004 represents about 420,000 birds and is significant enough for the current AHM model to recommend reduced hunter harvest.
The cause of the eastern mallard population decline is undetermined. Hypothesized reasons for the decline include loss of carrying capacity on breeding and non-breeding areas, reduction in “artificial” winter feeding activities in the NE states, over harvest, and the population exceeding carrying capacity and stabilizing at a lower equilibrium population near carrying capacity (e.g., like reintroduced wild turkey populations). Biologists are currently examining existing data sets (juvenile/adult age ratios and banding data) to identify potential issues with production and survival.
Atlantic Flyway biologists from the states and U.S. Fish & Wildlife Service are currently working towards a new multi-stock AHM model that will include mallards and four additional species including green-winged-teal, wood duck, ring-necked duck and goldeneye. Collectively, these species make up about 60% of the Atlantic Flyway duck harvest. Consequently, hunters will likely retain liberal or moderate season packages (60 and 45 days, respectively). Despite this forthcoming change, the Atlantic Flyway is proposing to reduce the mallard daily bag limit from 4 to 2 starting in 2019. Modeling suggests that reducing the bag in this manner will reduce harvest by 25% and achieve a sustainable harvest level.
Ramifications of the observed decline are complex and extend beyond eastern mallards. Like eastern mallards, the American black duck, a flagship species of the Atlantic Coast Joint Venture and high priority NAWMP species, harvest is managed via a species-specific AHM model. Within the black duck AHM model it is hypothesized that the abundance of eastern mallards adversely impacts the black duck population via reduced production. The mechanism for this potential impact is via competition during the breeding season as these species are closely related both morphologically and genetically. There is also potential for hybridization between these two species where they overlap on non-breeding areas. Thus, there are potential tradeoffs when considering management decisions surrounding these two species.
There is concern that the declining eastern mallard population and proposed bag restriction will catch Atlantic Flyway hunters off guard and potentially result in reductions in hunter numbers, private habitats managed for waterfowl, and funding for habitat programs. Thus, there is an opportunity for DU to play a proactive role in communications surrounding this issue. At a minimum, consideration should be given towards more holistic reporting regarding breeding waterfowl population status beyond the Mid-continent (Traditional Survey Area encompassing the PPR). Additional communications strategies should also be discussed regarding proposed changes to harvest regulations coming in 2019.
DU should also be prepared to consider engaging in science efforts to identify causes and solutions where warranted. In addition, if habitat carrying capacity is identified as a bottleneck, DU will certainly have a role to play in restoration of wetlands and associated uplands. Finally, as this issue unfolds over the course of the next two years, the waterfowl management system will continue working as designed, adapting to new information, and enabling refinement of DU’s role in the northern Atlantic Flyway states and provinces.
John Coluccy, DU’s Director of Conservation Planning for the Great Lakes/Atlantic Region